Virginia Huxley | University of Missouri-Columbia (original) (raw)

Papers by Virginia Huxley

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Feb 15, 2011

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Dec 23, 2016

Background and Objectives: The corneal epithelium provides a protective barrier against pathogen ... more Background and Objectives: The corneal epithelium provides a protective barrier against pathogen entrance and abrasive forces, largely due to the intercellular junctional complexes between neighboring cells. After a prescribed duration at the corneal surface, tight junctions between squamous surface cells must be disrupted to enable them to desquamate as a component of the tissue homeostatic renewal. We hypothesize that matrix metalloproteinase (MMPs) are secreted by corneal epithelial cells and cleave intercellular junctional proteins extracellularly at the epithelial surface. The purpose of this study was to examine the expression of specific MMPs and tight junction proteins during both the light and dark phases of the circadian cycle, and to assess their temporal and spatial relationships in the Xenopus laevis corneal epithelium. Methodology/Principal Findings: Expression of MMP-2, tissue inhibitor of MMP-2 (TIMP-2), membrane type 1-MMP (MT1-MMP) and the tight junction proteins occludin and claudin-4 were examined by confocal double-label immunohistochemistry on corneas obtained from Xenopus frogs at different circadian times. Occludin and claudin-4 expression was generally uniformly intact on the surface corneal epithelial cell lateral membranes during the daytime, but was frequently disrupted in small clusters of cells at night. Concomitantly, MMP-2 expression was often elevated in a mosaic pattern at nighttime and associated with clusters of desquamating surface cells. The MMP-2 binding partners, TIMP-2 and MT1-MMP were also localized to surface corneal epithelial cells during both the light and dark phases, with TIMP-2 tending to be elevated during the daytime. Conclusions/Significance: MMP-2 protein expression is elevated in a mosaic pattern in surface corneal epithelial cells during the nighttime in Xenopus laevis, and may play a role in homeostatic surface cell desquamation by disrupting intercellular junctional proteins. The sequence of MMP secretion and activation, tight junction protein cleavage, and subsequent surface cell desquamation and renewal may be orchestrated by nocturnal circadian signals.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Jul 28, 2018

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Dec 6, 2010

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Jan 5, 2018

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Sep 1, 2015

The FASEB Journal, Apr 1, 2014

The FASEB Journal, Apr 1, 2013

American Journal of Physiology-heart and Circulatory Physiology, Jun 1, 1993

We have developed a new method for quantification of arteriolar hydraulic conductivity (Lp) from ... more We have developed a new method for quantification of arteriolar hydraulic conductivity (Lp) from isolated rat brain vessels. The volume flux of water per unit surface area across the arteriole wall (Jv/S) was assessed from measurements of silicon oil drop movement within an occluded vessel at two to three pressures (between 20 and 70 mmHg); the Lp was derived from the slope of the relationship between Jv/S and applied pressure. Lp was measured in isolated cerebral arterioles 1) at room temperature (22 degrees C) without spontaneous vessel tone (control Lp; n = 11), 2) at room temperature with 10(-4) M adenosine (n = 5), and 3) at 37 degrees C with vessels dilated submaximally with 10(-4) M adenosine (n = 6). Lp at 22 degrees C without adenosine was 13.2 +/- 4.2 x 10(-9) (+/- SE) cm.s-1.cmH2O-1 for all vessels studied. Lp values ranged from 1.2 to 44.1 x 10(-9) cm.s-1.cmH2O-1 with a median value that was 5.9 x 10(-9) cm.s-1.cmH2O-1. Lp increased significantly (on average, 2.6-fold) with adenosine at 37 degrees C but not with adenosine at 22 degrees C. Control Lp bore no relationship to either the development of spontaneous tone or the diameter response to pH change, two recognized indicators of vessel viability.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Aug 21, 2012

The purpose of this project was to study the effects of various resuscitation fluid protocols in ... more The purpose of this project was to study the effects of various resuscitation fluid protocols in a systemically thermally injured rat sustaining 70% body surface area third degree burn using the pial window model in rats. The results show that there was a significant albumin leak in the cerebral vessels in both the experimental group which underwent no resuscitation fluid, as well as the experimental group that was resuscitated with Lactated Ringer's solution using the Parkland formula. When this was compared to the control group, as well as to the experimental group which received hypertonic hyperosmotic saline (HMS) boluses every hour, there was little if any leakage seen.

Contribution: Computerized Vasculature Image analysis • We are building a semi-automatic computer... more Contribution: Computerized Vasculature Image analysis • We are building a semi-automatic computerized image analysis system for Dura Mater vascular network from fluorescence microscopy [1].

American Journal of Physiology-Heart and Circulatory Physiology, 1990

Acute plasma volume reduction by atrial natriuretic peptide (ANP) may be mediated, at least in pa... more Acute plasma volume reduction by atrial natriuretic peptide (ANP) may be mediated, at least in part, by increased exchange vessel water conductivity (Lp). The present study tests the hypothesis that physiological levels of ANP acutely and reversibly elevate single capillary Lp. Paired, in situ measurements of Lp were obtained using the modified Landis technique in individually perfused mesenteric capillaries of the frog, Rana pipiens. Control Lp measurements ranged from 0.1 to 40 x 10(-7) cm.s-1.cmH2O-1 (with a median value of 2.5 x 10(-7] in 81 microvessels perfused with frog Ringer solution containing dialyzed bovine serum albumin. Vessels were recannulated and perfused with one or more concentrations of human ANP (hANP) spanning the physiopathological range: 0.01, 0.1, 1, 10, and 100 nM. When possible, a final recannulation and Lp determination was performed in the absence of hANP. A median 2.2-fold rapid Lp increase was observed compared with control at each peptide concentratio...

F1000 - Post-publication peer review of the biomedical literature

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature, Dec 1, 2010

arXiv (Cornell University), Nov 2, 2018

Objective: to develop quantitative methods for the clinical interpretation of the ballistocardiog... more Objective: to develop quantitative methods for the clinical interpretation of the ballistocardiogram (BCG). Methods: a closed-loop mathematical model of the cardiovascular system is proposed to theoretically simulate the mechanisms generating the BCG signal, which is then compared with the signal acquired via accelerometry on a suspended bed. Results: simulated arterial pressure waveforms and ventricular functions are in good qualitative and quantitative agreement with those reported in the clinical literature. Simulated BCG signals exhibit the typical I, J, K, L, M and N peaks and show good qualitative and quantitative agreement with experimental measurements. Simulated BCG signals associated with reduced contractility and increased stiffness of the left ventricle exhibit different changes that are characteristic of the specific pathological condition. Conclusion: the proposed closed-loop model captures the predominant features of BCG signals and can predict pathological changes on the basis of fundamental mechanisms in cardiovascular physiology. Significance: this work provides a quantitative framework for the clinical interpretation of BCG signals and the optimization of BCG sensing devices. The present study considers an average human body and can potentially be extended to include variability among individuals.

In biomedical imaging using video microscopy, understanding large tissue structures at cellular a... more In biomedical imaging using video microscopy, understanding large tissue structures at cellular and finer resolution poses many image acquisition challenges including limited field-of-view and tissue dynamics during imaging. Automated mosaicing or stitching of live tissue video microscopy enables the visualization and analysis of subtle morphological structures and large scale vessel network architecture in tissues like the mesentery. But mosacing can be challenging if there are deformable, motion-blurred, textureless, feature-poor frames. Feature-based methods perform poorly in such cases for the lack of distinctive keypoints. Standard single block correlation matching strategies might not provide robust registration due to deformable content. In addition, the panorama suffers if there is motion blur present in a sequence. To handle these challenges, we propose a novel algorithm, Deformable Normalized Cross Correlation (DNCC) image matching with RANSAC to establish robust registration. Besides, to produce seamless panorama from motion-blurred frames we present gradient blending method based on image edge information. The DNCC algorithm is applied on Frog Mesentery sequences. Our result is compared with PSS/AutoStitch [1, 2] to establish the efficiency and robustness of the proposed DNCC method.

The FASEB Journal, Mar 1, 2008

Mosaicing or large scale panoramic image generation is a crucial task in medical imaging especial... more Mosaicing or large scale panoramic image generation is a crucial task in medical imaging especially examining cellular features or microstructures. Earlier we have proposed an algorithm, Deformable Normalized Cross Correlation (DNCC) [1] to mosaic feature-poor, motion-blurred frog mesentery video sequences. DNCC algorithm generates a single mosaic from each sequence establishing broad structure morphology. Unfortunately, a single mosaic cannot incorporate all information captured from all the sequences together. In another word, we aim to generate a global mosaic combining or fusing all the single mosaics from mesentery sequences. Global mosaic is desirable for comprehensive observation and exploration of the target region in microscopic resolution. Unfortunately, registration of single mosaics to a global mosaic is challenging due to the perspective distortion, scale change and visible seam of single mosaics which are introduced during stitching. Traditional feature based or correlation based method do not work well in such cases. To handle these challenges, we propose a new fused descriptor combining the strengths of both feature based and correlation based registration method for fusing/stitching the single mosaics into one global mosaic or panorama.

Segmenting microvascular structures is an important requirement in understanding angioadaptation ... more Segmenting microvascular structures is an important requirement in understanding angioadaptation by which vascular networks remodel their morphological structures. Accurate segmentation for separating microvasculature structures is important in quantifying remodeling process. In this work, we utilize a deep convolutional neural network (CNN) framework for obtaining robust segmentations of microvasculature from epifluorescence microscopy imagery of mice dura mater. Due to the inhomogeneous staining of the microvasculature, different binding properties of vessels under fluorescence dye, uneven contrast and low texture content, traditional vessel segmentation approaches obtain sub-optimal accuracy. We consider a deep CNN for the purpose keeping small vessel segments and handle the challenges posed by epifluorescence microscopy imaging modality. Experimental results on ovariectomized — ovary removed (OVX) — mice dura mater epifluorescence microscopy images show that the proposed modified CNN framework obtains an highest accuracy of 99% and better than other vessel segmentation methods.